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Thursday, 30 January 2014 11:19

National Grid flood defence spend highlights need to protect UK critical infrastructure

National Grid’s latest Interim Management Statement published today says that its recent investment in flood defences in the UK has minimised the impact of recent bad weather - once again highlighting the need for the UK to protect its critical national infrastructure.

The statement says that to date National Grid has delivered good network performance for customers despite adverse winter weather conditions in its UK and US markets.

The Grid said that in the UK recent investment in flood defences for critical sites over the past few years had helped to minimise any cost or reliability impact on National Grid’s operations from recent bad weather.

Extremely cold weather in the US in recent weeks included an ice storm in upstate New York and Massachusetts in December which resulted in around 150,000 customers being temporarily without power.  

The statement said that disruption and costs related to extreme weather to date have been much lower than in the previous two years.

Following the flood events of 2007 and more recently localised flooding, National Grid undertook a range of activities in order to understand the impact on current assets within the network in order protect them assets and ensure safe operation in the future. The information enabled the Grid to advise on suitable designs for new assets and put in place preventative measures for current assets.

Work started as long ago as 2008 with the determination of flooding risk which involved gathering data from National Grid, the Environment Agency and the British Geological survey to determine risk of flooding to the distribution system. Flood mitigation work was then prioritised at 11 substation sites at risk of a 1 in 100-year fluvial (river) and tidal flood event and assessments of the risks posed from other sources of flooding, including extreme rainfall, were also carried out.

The Grid now has a 1.7km mobile flood defence system in place which can be deployed to substations anywhere in the country within 12-24 hours. All new substations and gas compressor stations are designed to be resilient to a 1 in 1,000-year flood event.

Some fifty-seven substations were also identified as potentially vulnerable to flooding, due to their co-location with power stations. The Grid said in November 2011 that "no immediate threats were foreseen if the Environment Agency maintains flood defences to existing protection standards."

Need to protect UK critical national infrastructure once again highlighted

The potential risks to the UK’s critical infrastructure as a result of more frequent and prolonged floods has the potential to become a more important political issue in the run-up to the next General Election.

The 2007 floods highlighted the vulnerability of key national infrastructure when widespread flooding led to power failures and loss of water supplies. Key areas of damage included:

  • flooding of the Mythe water treatment works in Gloucestershire which led to the loss of water supplies to 350,000 people for up to 17 days
  • motorway closures affected large parts of the road network with repair costs of local and trunk roads estimated at £40-60 million.
  • damage to electricity distribution assets cut off 40,000 people in Gloucestershire for 24 hours, with a further 9000 customers in Yorkshire and Humberside placed on rolling blackouts for several days.
  • a near-miss at Walham substation in Gloucestershire which came close to failure and could have led to loss of power to 500,000 people
  • a near breach of the Ulley Reservoir dam threatened other infrastructure assets including the M1 motorway, a major electricity substation and a gas network connection for Sheffield.

Cabinet Office reports on plans to make UK infrastructure more resilient

In November last year the Cabinet Office published A Summary of the UK’s 2013 Sector Resilience Plans. The national infrastructure is categorised into nine sectors: Communications, Emergency Services, Energy, Finance, Food, Government, Health, Transport and Water .

The UK’s national infrastructure is defined by the Government as:

“those facilities, systems, sites and networks necessary for the functioning of the country and the delivery of the essential  services upon which daily life in the UK depends”.

Working with infrastructure owners and regulators, the Government departments responsible for the nine national infrastructure sectors are required to produce Sector Resilience Plans on an annual basis. For 2013, Plans have also been produced for the Nuclear and Hazardous Sites sectors. The process is coordinated by the Civil Contingencies Secretariat (based in the Cabinet Office). Flooding is identified as one of the ongoing and principal risks to the UK’s critical infrastructure.

This is the fourth round of Sector Resilience Plans which allow departments to review the resilience of their most important infrastructure to all risks (threats and hazards). However, as classified information the individual plans for each sector are not publicly available owing to their sensitive nature. The Cabinet Office document provides an unclassified summary of the 2013 Plans.

Irrespective of risk, water firms required by law to provide water

According to the Cabinet Office, the water sector’s  Resilience Plan says that an all risks regulatory framework, mutual aid agreements and high levels of investment continue to strengthen the resilience of the water industry to major risks.

On assessment of existing resilience, the Cabinet Office paper says that irrespective of the risk, water companies are required by law to provide water by alternative means in the event of a failure of the mains supply. Key risks include:

  • disruption to electricity supplies resulting in the loss of mains water and affect the movement and treatment of sewage
  • loss of telecoms impacting remote flow management and monitoring systems

The Summary says that the water companies are continuing to develop multiple monitoring systems to reduce impacts of telecoms failure.

Building resilience in AMP6

For the period 2010-2015, Ofwat made £400m available to water companies to improve the resilience of their assets and systems to flooding and other natural hazards. On top of this a further £470m was made available to enhance the security of assets. In the 2014 Price Review the companies have once again been instructed to consider the resilience of assets to major risks in their business plans for 2015-2020.

 The Cabinet Office summary says that the Water Bill which is currently making its way through Parliament also contains a variety of measures to boost  the resilience of the water industry, including a primary resilience duty for Ofwat and a power for the Secretary of State to direct water companies to plan for a certain level of resilience. The Summary also says that other measures designed to improve innovation and efficiency should also contribute to enhanced resilience.

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